1. Field of the Invention
The present invention relates to a lock apparatus, more particularly to a lock apparatus which has an enhanced resistance to external impact and which has a lock core device that provides an enhanced anti-theft effect.
2. Description of the Related Art
U.S. Pat. No. 5,934,121 discloses block apparatus having a lock core unit and a coded key for operating the lock core unit. The lock core unit includes a stack of locking plates, each of which confines a central hole in a shape of three quarters of a circle to permit extension of the coded key therethrough. The locking plates have an outer periphery formed with engaging notches. The coded key has a cross-section in the form of a circular sector, and is formed with a plurality of key bit projections and key bit grooves which have inclined actuating surfaces at different angles to set the code of the key. The engaging notches are misaligned with one another in accordance with the code of the key when the lock core unit is in a locking position, and are aligned with one another when the lock core unit is in an unlocking position. When the key is inserted into a key hole of the lock core unit that is defined by the central holes of the locking plates, and is rotated to unlock the lock core unit, the locking plates rotate by different angles to align the engaging notches with one another to enable a locking rod of the lock core unit to extend into the aligned engaging notches and to disengage from a lock shell that houses the lock core unit so as to prevent the locking rod from hindering rotation of the lock core unit relative to a lock shell that houses the lock core unit. Misalignment of the engaging notches forces the locking rod to extend into a locking groove in the lock shell to hinder rotation of the lock core unit relative to the lock shell. Since the angles of the actuating surfaces of the key bit projections and the key bit grooves on the key can be varied in a range from 0 to 180 degrees, a relatively large number of codes can be set on the key. The lock apparatus thus has a good anti-theft effect. It is desirable to provide a lock apparatus that has a lock core unit of this type and capable of providing an enhanced anti-theft effect.
U.S. Pat. No. 5,931,030 discloses a padlock having a lock base, a lock core unit received in the lock base, and a U-shaped shackle with longer and shorter leg portions inserted removably into shackle insert holes in the lock base. A pair of catch members are disposed in a catch chamber within the lock base adjacent to the lock core unit. Each of the catch members has one end disposed adjacent to a plunger that is formed on a latch member of the lock core unit so as to be actuatable by the plunger, and an opposite end disposed adjacent to a respective one of the shackle insert holes for engaging a respective one of the longer and shorter legs of the shackle member. It is desirable to modify the connection between the catch members and the latch member to enhance the impact resistance of the catch members.
Therefore, the main object of the present invention is to provide a lock apparatus with an enhanced resistance to external impact and an enhanced anti-theft effect.
Accordingly, the lock apparatus of the present invention includes a lock body, a lock core device, a coded key, a shackle member, and a catch member. The lock body is formed with a lock core chamber, a lock core opening for access to the lock core chamber, and a shackle insert hole. The lock core chamber has a section formed as a catch chamber which is adjacent to and is communicated with the shackle insert hole. The lock core device is received in the lock core chamber via the lock core opening. The lock core device includes a cylindrical and axially rotatable lock core which is provided with a latch member that is disposed in the catch chamber. The latch member has an end face which is transverse to an axis of the lock core and which is formed with a pin hole that is eccentric to the axis of the lock core. The key is insertible into the lock core device via the lock core opening, and is operable for rotating the lock core and the latch member between locking and unlocking positions. The shackle member has a leg portion which is formed with a shackle groove and which is inserted into the shackle insert hole in the lock body. The catch member is disposed in the catch chamber of the lock body. The catch member has a shackle engaging end portion for engaging the shackle groove in the leg portion of the shackle member, and a latch engaging end portion opposite to the shackle engaging end portion and formed with a pin which extends rotatably into the pin hole in the latch member for engaging the latch member such that the catch member is movable between locking and unlocking positions when the latch member moves between the locking and unlocking positions. The shackle engaging end portion of the catch member extends into the shackle insert hole for engaging the shackle groove in the leg portion of the shackle member when the catch member is disposed in the locking position. The shackle engaging end portion is retracted into the catch chamber for disengaging from the leg portion of the shackle member to permit removal of the shackle member from the shackle insert hole when the catch member is disposed in the unlocking position.